Banks Lake Drawdown Environmental Impact Statement

Banks Lake Drawdown Final Environmental Impact Statement U.S. Department of the Interior Upper Columbia Area Office Bureau of Reclamation Ephrata Field Office Pacific Northwest Region Ephrata, Washington Boise, Idaho May 2004 MISSION STATEMENTS The mission of the Department of the Interior is to protect and provide access to our Nation’s natural and cultural heritage and honor our trust responsibilities to Indian tribes and our commitments to island communities. The mission of the Bureau of Reclamation is to manage, develop, and protect water and related resources in an environmentally and economically sound manner in the interest of the American public. Final Environmental Impact Statement Banks Lake Drawdown Douglas and Grant Counties, Washington Lead Agency: U.S. Department of the Interior Bureau of Reclamation For further information contact: Jim Blanchard Special Projects Officer Ephrata Field Office Bureau of Reclamation Box 815 Ephrata, WA 98823 (509) 754-0226 The Action Alternative describes the resource conditions that would occur with Banks Lake water surface elevations between 1570 feet and 1560 feet, while the No Action Alternative describes the conditions that would occur without the action, with water surface elevation between 1570 feet and 1565 feet. Both the No Action and Action Alternatives include four potential operational scenarios that could occur annually within their respective ranges, depending upon the hydrology of any given year. Both alternatives include refilling the reservoir to elevation 1570 feet by September 22. The No Action Alternative is the preferred alternative. The draft environmental impact statement provided Reclamation’s determination that the Action Alternative “may affect but is not likely to adversely affect” the federally listed bald eagle (Haliaeetus leucocephalus) and would have no effect on the federally listed pygmy rabbit (Brachylagus idahoensis) or Ute ladies’-tresses (Spiranthes diluvialis). The U.S. Department of the Interior’s Fish and Wildlife Service concurred with this assessment in a letter dated April 3, 2003, as part of the consultation process in compliance with section 7(a)(2) of the Endangered Species Act of 1973 as amended and codified in 50 CFR 402. This analysis was done in compliance with Action 31 of the Reasonable and Prudent Alternative under the December 2000 Biological Opinion issued by the National Marine Fisheries Service (NMFS) (currently National Oceanic Atmospheric Administration [NOAA] Fisheries) for operation of the Federal Columbia River Power System. Therefore, additional ESA consultation with NOAA Fisheries is not necessary. Summary In December 2000, the National Marine Fisheries Service (NMFS—now the National Oceanic and Atmospheric Administration [NOAA] Fisheries) issued a Biological Opinion (BiOp) to the Bureau of Reclamation, Bonneville Power Administration, and the U.S. Army Corps of Engineers for the operation of the Federal Columbia River Power System (NMFS 2000). The BiOp included a Reasonable and Prudent Alternative (RPA), of which Action 31 advised the Bureau of Reclamation (Reclamation) to “assess the likely environmental effects of operation of Banks Lake up to 10 feet down from full pool during August.” Reclamation completed RPA Action 31 by preparing the Banks Lake Drawdown environmental impact statement (EIS), which describes and analyzes the environmental effects of lowering the August water surface elevation of Banks Lake annually to elevation 1560 feet, which is 10 feet below full pool of elevation 1570 feet. Purpose and Need The purpose of the action is to enhance the probability of meeting flow objectives in the Columbia River at McNary Dam by altering the August drawdown of Banks Lake from water surface elevation 1565 feet to water surface elevation 1560 feet annually. The action would enhance flows during the juvenile out-migration of Endangered Species Act (ESA) listed salmonid stocks (specifically Snake River fall chinook salmon) during August. This analysis complies with Action 31 of the Reasonable and Prudent Alternative of the Federal Columbia River Power System Biological Opinion, issued by the National Marine Fisheries Service (now National Oceanic and Atmospheric Administration [NOAA] Fisheries) on December 21, 2000. The need is to provide increased flows in the Columbia River for ESA-listed salmonid stocks by modifying Banks Lake’s operations. Issues The issues identified during the scoping process and considered throughout the discussion of the affected environment and environmental consequences in the EIS are: S-1 Banks Lake Drawdown Final Environmental Impact Statement • Lake elevations, instream flows, and water quality • Irrigation deliveries • Fish and wildlife • Threatened and endangered species • Recreation • Public safety—roads, boating, and fire hazards • Cultural resources • Economics, particularly for local economy and power General Description of the Area Banks Lake, one of the principal reservoirs of the Columbia Basin Project (CBP), lies primarily within Grant County, but portions of the western shoreline extend into Douglas County. Banks Lake is a reregulating reservoir, which was created by damming the Grand Coulee with two damsthe North Dam and the Dry Falls Dam. The active capacity of Banks Lake is 715,000 acre feet; the reservoir’s full pool elevation is 1570 feet. The lands surrounding the lake support a rich vegetative mosaic of shrub-steppe, mesic shrub, upland forest, and riparian/wetland communities, many of which the Washington Department of Fish and Wildlife (WDFW) has identified as “priority habitats.” The area supports a variety of wildlife. The riparian habitats along perennial streams and shorelines provide important winter roosting areas for many bird species, including the bald eagle. The islands at the southern end of the reservoir provide habitat for colonial nesting birds and waterfowl. Important waterfowl breeding areas include Devil’s Punch Bowl, Osborn Bay, and the wetlands and waters located at the south end of Steamboat Rock peninsula and below Dry Falls Dam. Alternatives Two alternatives are described and analyzed in this EIS. The first alternative is the No Action Alternative, which describes the Banks Lake August water surface elevations that would occur if Reclamation decided not to implement the Action Alternative. Four scenarios are presented on how the water surface elevation 1565 feet by August 31 could be achieved. These scenarios vary, depending upon the hydrology of any particular year. The Action Alternative describes the proposed operational modification of August water surface elevations to achieve elevation 1560 feet by August 31. There may be conditions when Reclamation would not provide the drawdowns described in the No Action and Action Alternatives. In addition, in some years drawdowns may be more than that described in the alternatives. Conditions that may trigger a lesser or greater drawdown could include, but are not limited to S-2 Summary (1) mechanical limitations to pumping capacity, (2) low water years when flows in September are predicted to be insufficient to supply refill water, (3) high water years when the contribution of Banks Lake is not needed to meet flow targets, (4) years when energy demand is predicted to limit the amount of power available for refill during early September, and (5) drawdowns for maintenance needs. Even during years with these types of conditions, partial drawdowns might be possible. Conditions that would preclude drawdowns are anticipated to occur infrequently. For the analysis in this EIS, it is assumed that Banks Lake would be operated as described in the alternatives, with the scenario to be implemented based only on the hydrology of a given year. Impacts resulting from the infrequent changes to the described operation would be evaluated on a case specific basis with appropriate National Environmental Policy Act (NEPA) compliance being conducted at that time. No Action Alternative—Preferred Alternative Under No Action, Banks Lake water surface would normally range between water surface elevation 1570 feet and water surface elevation 1565 feet between August 1 and September 22. The goal and maximum possible draft of Banks Lake in August would be from water surface elevation 1570 feet to 1565 feet, based on RPA Action 23 of NMFS 2000 BiOp, which states that Reclamation shall operate Banks Lake at an elevation 5 feet from full pool during August. Approximately 133,600 acre-feet of water, the volume between elevation 1570 and 1565 feet, would be available to increase streamflow for fish migration targets during August. Under the No Action Alternative, Reclamation would still have the discretion to manage the lake level to other water surface elevations for authorized purposes. Three different scenarios to draft this volume of water in August were modeled, while another scenario assumed no draft during August. All four scenarios, as shown in figure S-1, are evaluated in the EIS. Scenarios consist of Low Water, an Early Draft, a Uniform Draft, and a Late Draft. The Low Water scenario assumes that Banks Lake is at water surface elevation 1565 feet on August 1, while the remaining three scenarios assume that the water surface is at elevation 1570 feet on August 1. Drawdown The four different drawdown scenarios have been developed to show the range of conditions that may occur, depending upon the hydrology, as the lake is operated between water surface elevations 1570 and 1565 feet. 1. Low Water Banks Lake water surface elevation at 1565 feet on August 1 and held at that elevation until August 31. Would begin drawdown no earlier than July 22. Average rate of draft during August = 0.0 feet per day. S-3 Banks Lake Drawdown Final Environmental Impact Statement 2. Early Draft Draft Banks Lake water surface elevation from 1570 feet on August 1 to elevation 1565 feet on August 10. Average rate of draft = 0.5 foot per day. 3. Uniform Draft Draft Banks Lake water surface elevation from 1570 feet on August 1 to 1565 feet on August 31. Average rate of draft = 0.16 foot per day. 4. Late Draft Draft Banks Lake water surface elevation from 1570 feet on August 22 to 1565 feet on August 31.

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